Counterweight suspension structure in a circuit breaker



Nov. 30, 1965 R. NICOL 3,221,122

GOUNTERWEIGHT SUSPENSION STRUCTURE IN A CIRCUIT BREAKER Filed Jan. 18, 1963 3 Sheets-Sheet 1 INVENTOR. RONALD NICOL HIS QTTOIZNEVS R. NICOL Nov. 30, 1965 COUNTERWEIGHT SUSPENSION STRUCTURE IN A CIRCUIT BREAKER 3 Sheets-Sheet 2 Filed Jan. 18, 1963 SUSPENSION STRUCTURE l9 BROKEN nwnv HERE AND DQQTLY OMITTED FOR cuam-rv INVENTOR. RONALD Nucol. 3,335 :7

H15 ATTORNEYS Nov. 30, 1965 R. NICOL 3,221,122

COUNTERWEIGHT SUSPENSION STRUCTURE IN A CIRCUIT BREAKER Filed Jan. l8, 1965 I5 Sheets-Sheet 5 INVENTOR.

Y RONALD NICOL B mew! H15 HT7DR/UE S United States Patent 3,221,122 COUNTERWEIGHT SUSPENSION STRUCTURE IN A CIRCUIT BREAKER Ronald Nicol, Trenton, N.J., assignor to Heinemann Electric Company, Trenton, N.J., a corporation of New Jersey Filed Jan. 18, 1963, Ser. No. 252,413 11 Claims. (Cl, 200-111) This invention relates to electric circuit breakers and, more particularly, to an improved vibration and shock resistant counterweight suspension structure for an axially movable tube which acts as an armature for the coil of the electromagnet controlling the opening of the contacts on predetermined overload conditions.

It is an object of this invention to provide a counterweight suspension structure which performs satisfactorily at low magnetornot'ive force levels on the tube and which requires a minimum amount of adjustment after assembly.

In one embodiment, this invention is used in a circuit breaker provided with a pair of separable contacts, one of the contacts being mounted upon a movable contact arm, the latter being pivotal from a contacts closed position to a contacts open position and suitably biased by a spring to the open contacts position. A linkage mechanism is provided connected to the movable arm and provided with a handle for manually opening and closing the contacts. The linkage is controlled electromagnetically by an electromagnet which includes the coil and the tube, the latter being movable axially relative to the coil on predetermined overload currents.

The linkage mechanism is mounted between two frame plates which also support the coil. The suspension plates of the suspension structure are pivotally mounted to the tube on opposite sides thereof and to the frame plates. Each suspension plate is provided with a spring mounted at one end to a bendable arm carried by one of the frame plates, on one side of the pivotal mounting between the frame plate and the suspension plate, and at the other end between the pivotal mountings of the suspension plate to the same frame plate and the tube.-

When the pivotal connection between the suspension plate andthe tube is above the pivotal connection between the frame plate and the suspension plate, the spring helps move the tube upwardly, but when below, the spring helps move the tube downwardly.

To counterbalance the tube, the ends of the suspension plates are interconnected and provided with a weight, for balancing the weight of the tube about the frame pivotal connection, so that vibrations and shocks will tend not to actuate the tube.

The foregoing and other objects of the invention, the principles of the invention, and the best mode in which it is contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

In the drawings,

FIG. 1 is a view, partly in section and partly in elevation, of a circuit breaker incorporating this invention with the linkage illustrated in the contacts open position;

FIG. 2 is a sectional view taken along the line 22 in FIG. 1 but unlike FIG. 1 the mechanism is shown when an overload suflicient to open the contacts energizes the coil but the handle is held in the contacts closed position omitting a part of the counterweight suspension structure for clarity;

FIG. 3 is a view taken along the line 3-3 in FIG. 2 but illustrating the part of the counterweight suspension structure omitted in FIG. 2;

FIG. 4 is a partial perspective view of the counterweight suspension structure illustrating its relationship to the frame plates; and

3,221,122 Patented Nov. 30, 1965 FIG. 5 is a view similar to FIG. 2 but illustrating only the counterweight suspension structure, the tube and the frame plates.

Referring to the drawings, a circuit breaker 10 is illustrated having a metallic case 11, partly broken away in FIG. 1 to expose certain internal structure, through which extend terminals 12 and 13. The terminal 13 includes a stationary contact 15 at its upper end which cooperates with a movable contact 17 carried by a movable arm 18. The movable arm 18 is actuated by a link-age mechanism 24} controlled by an electromagnetic device 16, a counterweight suspension structure 19 being associated with the latter, the terminals 12 and 13, the electromagnetic device 16 and the linkage mechanism 20 being all described in detail and claimed in applications filed by Raymond B. Heilman and Harold H. Bahr on December 24, 1962, Serial No. 246,699; by Raymond B. Heilman on Janu ary 18, 1963, Serial No. 252,404; and by Raymond B. Heilman on January 18, 1963, Serial No. 252,485; and consequently they are not described in detail herein. Manual opening and closing of the contacts 15 and 17 is eifec-tuated by a handle 21, whereas electromagnetic tripping of the contacts to the open position is controlled by the downward movement of the tube 26.

The linkage mechanism 20 comprises two groups of links referred to for convenience as the handle toggle or first group 23 and the main toggle or second group 24. Briefly, pivotal counterclockwise movement of the handle 21, starting from the open contacts position of FIG. 1, causes the handle toggle group of links 23 comprising the handle link 27 and a link of varying length 28 (joined together by a knee pintle 30) to move to the right and the handle force to be transmitted by a coupling link 32, from the link of varying length 28 to the knee pintle 33 of the main toggle links 24, the latter comprising the toggle links 36 and 37 and the catch link 39. The lower toggle link 37 is, in turn, connected to the movable contact arm 18, whereby movement of the handle 21 results in the movable arm 18 being rotated in the counterclockwise direction, closing the contacts 15 and 17. in the closed position of the contacts, the catch link 3'9 is restrained from movement by a lock 45 carried by a cradle 46. In turn, the cradle 46 is restrained by the lock 52 (the latter shown in FIG. 3 after release of the cradle 46) from moving in the counterclockwise direction (due to the bias imposed on the cradle 46 by the catch link 39) from the force of the opening springs 47.

When the tube 26 moves downwardly a sufficient distance, upon predetermined overloads, the tube 26 pivots clockwise (FIGS. 1 and 3) the counterweight suspension structure 19 sufliciently to pivot the lock 52 and rotate the latter in the clockwise direction also. Sufficient clockwise rotation of the lock 52, FIG. 3, results in the release of the cradle 46 from the lock 52, whereby the catch link 39 is released from its lock 45 and the upper end of the catch link 39 moves in the clockwise direction under the bias of the opening springs 47, FIG. 1. This clock- Wise movement of the catch link 39 causes the main toggle (formed by links 36 and 37) to collapse due to the pressure of the opening springs 47, whereupon the contacts open. During the collapse of the main toggle links, the knee pintle 30 of the handle toggls is moved overcenter (toward the left) sufficiently for the spring 56 (carried by the link of varying length 28) to help reset the mechanism.

The terminal 13 is connected by a conductor 58 to the coil 59 of the electromagnet 16, the coil 59 being connected by a flexible conductor 55 to the movable arm 18, thereby completing the electrical circuit when the contacts are closed.

The counterweight suspension structure 19, FIGS. 2, 4 and 5, comprises two counterweight plates 60 and 61 pivotally connected to diametrically opposite sides of the tube 26 by pins 63 and 64, the linkage mechanism and frame plates 72 and 73 being intermediate the plate 60 and 61, as illustrated. The pins 63 and 64 are formed and carried by a strap 66 which frictionally and tightly engages the outer surface of the tube 26 at a groove 67 (FIG. 1) provided for this purpose. The pins 63 and 64 are disposed to the righ of the linkage mechanism 20, since the tube 20 and the coil 59 are vertically aligned and the coil frame 98 is secured to the righ hand side of the frame plates 72 and 73 placing the entire electromagnetic structure 16 to the right of the linkage mechanism 20. Further, the pins 63 and 64 extend into holes which are slightly larger than the pins 63 and 64, to accommodate the small arcuate movement of the right hand end portions of the plates 60 and 61, so that a minimum amount of movement transverse to the vertical axis (along which the tube moves) is imposed upon the tube 26 by the pins 63 and 64.

The counterweight plates 60 and 61 are pivotally supported intermediate their ends by pins 68 and 69 secured to and carried at one end by bendable arms 70 and 71. The pins 68 and 69 are staked at their ends to retain the plates 60 and 61, the arms 70 and 71 abutting portions of the linkage frame plates 72 and 73 and being welded (at portions of their right hand ends only to the left of pins 68 and 69) to the frame plates 72 and 73, as illustrated in FIG. 5.

Elongated tension springs 75 and 76 (one for each of the plates 60 and 61) are provided to bias the pins 63 and 64 to positions above or below the pins 68 and 69, and for this purpose the plates 60 and 61 are provided with holes 87 and 88 intermediate the pins 63 and 64 and the pins 68 and 69, and in line therewith, into which extend the right hand ends 78 and 79 of the springs 75 and 76, the left hand ends 81 and 82 of the springs 75 and '76 being secured in notches formed in the left hand ends of the arms 70 and 71, the notches also being in line with the pins 63, 64, 68 and 69 and the holes 87 and 88, as illustrated in FIG. 4, the latter being a view illustrating the tube 26 during its downward movement at that instant when the pins 63, 64, 68 and 69, the holes 87 and 88, and the notches of the arms 70 and 71 are horizontally aligned.

The arms 70 and 71 are provided with elongated holes 89, FIG. 4, to receive parts of the springs 75 and 76 and the counterweight plates 60 and 61 are bent, out away from the springs 75 and 76, as illustrated in FIG. 5, to clear the latter during pivotal movement.

Viewing each side of the counterweight suspension structure 19 separately, two symmetrical toggles are formed on opposite sides of the frame plates 72 and '73, i.e. on opposite sides of the linkage mechanism 20. That is, the bendable arm 71 and the portion of the plate 61 between the pin 69 and the hole 88 are the links of the one toggle with the pin 69 forming the knee thereof. Also, the bendable arm 70 and the portion of the plate 60 between the pin 68 and the hole 87 are the links of the other toggle with the pin 68 forming the knee thereof.

The left hand ends of the plates 60 and 61, to the left of the linkage mechanism 20, are connected by a pin 84 having counterweights 85 spaced from each other but in abutment with the plates 60 and 61, the pin 84 and weights 85 being of a mass and at a lever arm, determined by the much greater distance from the pin 84 to the pins 68 and 69, as compared to the smaller distance between the pins 63 and 64 and the pins 68 and 69 and the weight of the tube 26, which balances the tube 26 about the pins 68 and 69.

Hence, if there were no other forces on the tube 26, since the lines of action of the springs 75 and 76 would pass through the centers of the pins 63, 64, 68 and 69, and the counterweight formed by pin 84 and weights 85 balances the tube 26, no movement of the tube 26 would take place. However, as described in detail in the aforementioned c-opending patent application Serial No. 252,- 404, the lower end of the tube 26 is provided with a reset spring device 94 for moving the tube 26 to the upper or initial position illustrated in FIG. 1, after electromagnetic opening of the contacts, until the reset plate 95, which is carried by the tube 26, abuts the bearing 96 for the lower end of the tube 26. The reset device 94 comprises a torsion spring wound about a pin 101, the ends of the latter supported by the plates 72 and 73, having one end connected to the reset plate by extending through holes in the latter and the other end engageable with and stressed by the right hand end portion of movable arm 18 when the latter is in the open contacts position and not so engageable when the movable arm is in the contacts closed position, at which latter time the spring is relaxed and imposes no force on the tube 26.

When the tube is in the upper or initial position illustrated in FIG. 1, the pins 63 and 64 are disposed above the pins 68 and 69 and, hence, the springs 75 and 76 exert a force on the plates 60 and 61 tending to keep the pins 63 and 64 in this position, i.e., the tube 26 is biased upwardly by the springs 75 and 76 as Well as by the reset device 94.

An electromagnetic force in the downward direction is imposed upon the tube 26, which moves the tube 26 downwardly along its vertical axis (being coaxial with the coil 59) instantaneously at certain predetermined overloads or after a time delay period at other overloads, since the tube 26 is partly of magnetic material and houses a core (not illustrated) also of magnetic material. When the electromagnetic force on the tube 26 is sufficient to overcome the upward bias on the tube 26 imposed only by the springs 75 and '76 (since, as previously described, the reset device 94 imposes no upward force on the tube 26 at this time) downward movement of the tube commences. When the pins 63 and 64 (in their downward movement) pass the center of the pins 68 and 69, the springs 75 and 76 impose on the pins 63 and 64 a down ward force, helping downward movement of the tube 26 toward its lower or second position wherein the tube shoulder 97 abuts the top of the coil frame 98, this latter position being illustrated in FIG. 3, at which time the pins 63 and 64 are below the pins 68 and 69.

The lock 52 is biased by a spring 104 counterclockwise so that the right hand end of the lock 52 is always in engagement with a depending arm 105 formed on the plate 61 below the pin 64, the spring 104 being secured at one end to the frame plate 73 and at the other end to the lock 52 to the left of a pin 107 which pivotally connects the lock 52 to the frame plate 73. During the downward movement of the tube 26, the depending arm 105 pivots the lock 52 about its pin 107, rotating the lock 52 clockwise (FIG. 3) so as to release the cradle 46.

Thus, the pins 63 and 64 and the plates 60 and 61 pivotally suspend the tube 26 about the fixed pins 68 and 69 and the counterweights 85 balance the tube 26 about the pins 68 and 69, while the tube 26 is allowed to move axially, vertically guided by the bearing 96 (the latter fixed to the magnetic frame 98), as the pins 63 and 64 move arcuately about the fixed pins 68 and 69 from a position above the pins 68 and 69 to a position below the pins 68 and 69 or in the opposite direction from a position below the pins 68 and 69 to a position above the pins 68 and 69.

Since the arms 70 and 71 are of sheet metal and fixed to the frame plates only along part of their length at their right hand end portions, proper alignment of the springs 7 5 and 76 may be achieved by bending the left hand end portions of the arms '70 and 71 up or down, as required.

Thus, a counterweight suspension structure 19 has been provided for the tube 26, the counterweight suspension structure being pivoted about the pins 68 and 69 carried by the frame plates 72 and 73 and being connected to the tube 26 by two other pins 63 and 64, the structure 19 being such as to balance the tube 26 about the pins 68 and 69 and such that the springs 75 and 76 help in movement toward or away from the coil after a certain initial movement of the tube has taken place toward or away from the coil as determined by the energization of the coil 59 or the reset device 94.

Having described this invention, I claim:

1. In a circuit breaker comprising the combination of stationary and movable contacts, a mechanism for actuating the movable contact, a frame supporting said mechanism, an electromagnet for controlling the mechanism, said electromagnet including a tube movable axially upon predetermined overload conditions, the improvement comprising a plate pivotally connected to said tube at a first end portion by a first pin, a counterweight balancing said tube at a second end portion of said plate, said plate being pivotally connected to said frame intermediate its end portions by a second pin, and spring means biasing said plate first end portion above the second pin when the first pin is above the second pin and biasing the first pin below the second pin when the first pin is below the second pin.

2. In a circuit breaker comprising the combination of stationary and movable contacts, a mechanism for actuating the movable contact, a frame plate for supporting said mechanism, an electromagnet for controlling the mechanism, said electromagnet including a tube movable axially upon predetermined overload conditions, the improvement comprising spaced suspension plates pivotally connected to opposite sides of said tube at first end portions by a first pair of pins, a counterweight connected to both suspension plates for balancing said tube at second end portions of said suspension plates, said suspension plates being pivotally connected to said frame plates inter-.

mediate said suspension plate end portions by a second pair of pins, two springs one of which is connected at one end to one of said frame plates and to one of said suspension plates intermediate the aforementioned pivotal connections of this suspension plate and in line with both pivotal connections, the other spring being connected at one end to the other frame plate and to the other suspension plate intermediate the a-forementioned pivotal connections of this suspension plate and in line with both pivotal connections, whereby said springs bias said first suspension plate end portions above said second pair of pins when said first pair of pins are above said second pair of pins and said springs bias said first pair of pins below said second pair of pins when said first pair of pins are below the second pair of pins.

3. In a circuit breaker comprising the combination of stationary and movable contacts, a mechanism for actuating the movable contact, a frame plate for supporting said mechanism, an electromagnet for controlling the mechanism, said electromagnet including a tube movable axially upon predetermined overload conditions, the improvement comprising spaced suspension plates pivotally connected to opposite sides of said tube at first end portions by a first pair of pins, a counterweight connected to both suspension plates for balancing said tube at second end portions of said suspension plates, two spaced, bendable arms each of which is fixed to one of said frame plates, said suspension plates being pivotally connected to said frame plates intermediate their end portions by a second pair of pins, two springs one of which is connected at one end to one of said arms and at the other end to one of said suspension plates intermediate the aforementioned pivotal connections of this suspension plate and in line with both pivotal connections, the other spring being connected at one end to the other arm and at the other end to the other suspension plate intermediate the aforementioned pivotal connections of this suspension plate and in line with both pivotal connections, whereby said springs bias said first suspension plate end portions above said second pair of pins when said first pair of pins are above said second pair of pins and said 6 springs bias said first pair of pins below said second pair of pins when said first pair of pins are below the second pair of pins.

4. The structure recited in claim 3 and further including a trigger formed on one of said suspension plates for depressing a latch to release said mechanism upon suitable movement of said tube.

5. In a circuit breaker comprising the combination of stationary and movable contacts, a mechanism for actuating the movable contact, a frame plate supporting said mechainsm, an electromagnet for controlling said mechanism, said electromagnet including a tube movable upon predetermined overload conditions, and spring means for returning said tube to an initial position after opening of the contacts due to an overload condition, the improvement comprising a plate pivotally connected to said tube at a first end portion by a first pin, a counterweight balancing said tube at a second end portion of said plate, said plate being pivotally connected to said frame plate intermediate its end portions by a second pin, and a tension spring having a first end pivotally connected to a fixed support and a second end pivotally connected to said plate intermediate said first and second pins thereby forming with said plate a toggle, the pivotal connection of said spring to said plate being in line with said first and second pins, said spring being movable by said plate about the pivotal connection of said spring to the fixed support upon movement of said tube, whereby upon downward movement of said tube, when said pivotal connection to said plate passes the center of said second pin, said spring imposes on said plate a downward force which is transmitted by the first pin to the tube.

6. In a circuit breaker comprising the combination of stationary and movable contacts, a mechanism for actuating the movable contact, a frame plate supporting said mechanism, an electromagnet for controlling said mechanism, said electromagnet including a tube movable upon predetermined overload conditions, and spring means for returning said tube to an initial position after opening of the contacts due to an overload condition, the improvement comprising a plate pivotally connected to said tube at a first end portion by a first pin, a counterweight balancing said tube at a second end portion of said plate, said plate being pivotally connected to said frame plate intermediate its end portions by a second pin, and a tension spring forming with said plate a toggle for biasing said first pin above said second pin when said first pin is above said second pin and for biasing said first pin below said second pin when said second pin is below said first pin.

7. In a circuit breaker comprising the combination of relatively movable contacts, a linkage mechanism for actuating one of said contacts, a frame plate for said mechanism, an electromagnetic structure for controlling said linkage mechanism, said electromagnetic structure including a coil disposed to one side of said linkage mechanism, said electromagnetic structure further including a tube movable axially along the axis of said coil upon predetermined overload conditions from an initial posi tion to a second position, and reset means to move said tube to its initial position upon deenergization of said coil, the improvement comprising a counterweight plate pivotally connected to said tube at a first end portion by a first pin, a counterweight balancing said tube at a second end portion of said counterweight plate which is opposite to the first end portion thereof, said counterweight plate being pivotally connected to said frame plate intermediate said end portions by a second pin, said second end portion of said counterweight plate being disposed on the opposite side of said mechanism relative to the side of said mechanism on which said tube is disposed, resulting in a compact arrangement wherein the linkage mechanism is disposed intermediate the tube and the counterweight therefor.

8. In a circuit breaker comprising the combination of relatively movable contacts, a linkage mechanism for actuating one of said contacts, frame plates intermediate which is disposed said mechanism, an electromagnetic structure for controlling said linkage mechanism, said electromagnetic structure including a coil disposed to one side of said linkage mechanism, said electromagnetic structure further including a tube movable axially along the axis of said coil upon predetermined overload conditions from an initial position to a second position, and reset means to move said tube to its initial position, the improvement comprising two counterweight plates pivotally connected by first end portions to opposite sides of said tube and intermediate which is disposed said linkage mechanism, a counterweight balancing said tube at second portions of said counterweight plates opposite to the first end portions thereof, said counterweight plates being pivotally connected to said frame plates intermediate their end portions, said second end portions of said counterweight plates being disposed on the opposite side of said mechanism relative to the side of said mechanism on which said tube is disposed, resulting in a compact arrangement wherein the linkage mechanism is disposed intermediate the tube and the counterweight therefor.

9. The structure recited in claim 7 and further including spring means connected at one end to said frame plate and at another end to said counterweight plate for biasing said tube above or below the pivotal connection between said counterweight plate and said frame plate depending on whether the pivotal connection between said counterweight plate and said tube is above or below the pivotal connection between said counterweight plate and said frame plate.

10. The structure recited in claim 8 and further including two spring means one for each counterweight plate, one spring means being connected at one end to one of the frame plates and at another end to one of the counterweight plates and the other spring means being connected at one end to the other frame plate and at another end to the other counterweight plate for biasing the tube above or below the pivotal connection between the associated counterweight plate and the associated frame plate depending on whether the pivotal connections between said counterweight plates and said tube are above or below the pivotal connections between said counterweight plates and said frame plates.

11. In a circuit breaker comprising the combination of stationary and movable contacts, a mechanism for actuating the movable contact, a frame supporting said mechanism, an electromagnet for controlling the mechanism, said electromagnet including an axially movable armature movable axially upon predetermined overload conditions, said mechanism including a latch, the im provement comprising a plate pivotally connected to said armature at a first end portion by a first pin, a counterweight balancing said armature at a second end portion of said plate, said plate being pivotally connected to said frame intermediate its end portions by a second pin, spring means biasing said plate first end portion above the second pin when the first pin is above the second pin and biasing the first pin below the second pin when the first pin is below the second pin, and said plate including a trigger for depressing said latch to release said mechanism upon suitable movement of said armature.

References Cited by the Examiner UNITED STATES PATENTS 1,573,095 2/1926 Saklatwalla et al. 200111 X 1,991,113 2/1935 Nette 20087 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCI-IAEFER, Examiner. 

1. IN A CIRCUIT BREAKER COMPRISING THE COMBINATION OF STATIONARY AND MOVABLE CONTACTS, A MECHANISM FOR ACTUATING THE MOVABLE CONTACT, A FRAME SUPPORTING SAID MECHANISM, AN ELECTROMAGNET FOR CONTROLLING THE MECHANISM, SAID ELECTROMAGNET INCLUDING A TUBE MOVABLE AXIALLY UPON PREDETERMINED OVERLOAD CONDITIONS, THE IMPROVEMENT COMPRISING A PLATE PIVOTALLY CONNECTED TO SAID TUBE AT A FIRST END PORTION BY A FIRST PIN, A COUNTERWEIGHT BALANCING SAID TUBE AT A SECOND END PORTION OF SAID PLATE, SAID PALTE BEING PIVOTALLY CONNECTED TO SAID FRAME INTERMEIDATE ITS END PORTIONS BY A SECOND PIN, AND SPRING MEANS BIASING SAID PLATE FIRST END PORTION ABOVE THE SECOND PIN WHEN THE FIRST PIN IS ABOVE THE SECOND PIN AND BIASING THE FIRST PIN BELOW THE SECOND PIN WHEN THE FIRST PIN IS BELOW THE SECOND PIN. 